Electromagnetic device



- H. w; GOFF,

ELECTROMAGNETIC DEVICE.

APPLICATION FILED FEB.'6, I919.

Patented June 13, 1922;

UNITED SIATES PATENT OFFICE...

HAROLD W. GOFF, OF NEW YORK, N. 'Yl, ASSIGNOR TO WESTERN ELECTRIC COMPANY,

INCORPORATED, OF NEW'YO RK, N;

Y., A CORPORATION OF NEW YORK.

ELECTROMAGNETIC DEVICE.

citizen of the United States, residing at New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Electromagnetic Devices, of which the following is a full, clear, concise, and exact description.

This invention relates to electromagnetic devices and more particularly to electromagnetic relays and step magnets. V

The principal object of the present in vention is to provide a simple andeflicient electromagnetic device in which the same energlzing winding or windings serve to attract two armatures, one of which will be slow releasing. In accordance with this fea ture of the invention an electromagnetic device is provided having two armatures arranged in normally parallel magnetic circuits, with an energizing winding 'or windings to effect attraction of both armatures' arranged so that the'field of force thereof traverses a portion of the normally parallel magnetic circuits which is common to both armature circuits, and in which a shortcircuited winding is arranged about a portion of the magnetic circuit of and individual to one of the armatures to render such ar1na ture slow to release.

Another object of the invention is to provide an electromagnetic device having an armature, the release of which, upon the interruption or predetermined diminution of the current through the attracting winding, will be accelerated by flux developed incidental to' such interruption or diminution. In accordance with this feature of the invention, an electromagnetic device, having an armature and an energizing winding orwindings to effect attraction or the arma' ture, is provided with a short-circuited sec ondary winding arranged about a magnetic circuit in oarallel with the normal magnetic circuit of the armature, in which the secondary winding develops flu); incidental to interruption or diminution ofthe current through the attracting winding or windings, having a direction, within the portion of the normal magnetic circuit of and including the armature, opposite to that of the flux residual in such normal magnetic circuit upon such interruption or diminution of current; whereby said armature is accelerated in its release.

Specification of Letters P'atent'. Patented June 13,

6,1919. Serial No.275,354.

A further object of the present invention is to provide an electromagnetic device ha-v ing two armatures' and an energizing winding or windings to efi'ect'attractionot both: armatures, the release of oneof which is made slow bysuitable means, and the release of the" other of which is accelerated upon interrup tion or predetermined diminution of the current through the attracting winding or windings by the operation of the same means by whichthe first armature is made slow releasing. In accordance with this featureof the invention, an electromagnetic device is provided having a pair of armatures arranged in normally parallel: magnetic circuits, with an energizing winding or Windings to eflt'ect attraction of botlr armatures arranged so-that' the field of force thereof traverses a portion of the normal magnetic circuits common to both armatures, and 113K ing onearmat'ure made slow to release by a short circuited secondary winding arranged about a; portion of its magnetic circuit, normally'individual thereto; the flux developed by the secondary winding; upon interrup= tion or predetermined diminutionofthe cur rent through the attracting winding or windings having a direction, within the portion of the normal magnetic circuit of and in cluding'the other armature, oppositet'o' the direction of the flux residual in the normal circuit of such other armature upon suchinterruption or predetermined diminution of current, to accelerate the release of such other armature. I

Still another object of the invention is to provide an electromagnetic device, having two armatures, in which the same en'ergiz ing winding. or windings serve to attract two armatures, the normal magnetic cir cuits of which have a portion in common, and in which flux, developed incidental to the interruption or diminution of the cur rent throughtheattracting winding or windings, will be of the same direction, within the magnetic circuit 0t one of the armatures and the portion of the magnetic circuitscommon to both armatures, as the direction of the" flux developed in the magi ieti'e circuit of the one armature and the portion of's'ueh magnetic circuits common to' both armatures by the attracting windin'g orlwindingspi'n lease'. the" invention an electromagnetic device provided with two armatures arranged in parallel magnetic circuits, with an energizing winding or windings to effect attraction of both armatures so positioned that the field of force thereof traverses a portion of the magnetic circuits which is common to both armatures, and in which a short-circuited secondary winding is arranged about a portion of the magnetic circuit of one armature which is normally individual thereto, and in which the flux developed by the secondary winding, upon interruption or diminution of the current through the attracting winding or windings, is of therame direction, within the ma gnetic circuit of its armature and the portion of the magnetic circuits comm on to both armatures, as the direc tion of the flux developed in the magnetic circuit of the one armature and the portion of the magnetic circuits common to both arma-tures by the attracting winding or windings; whereby such armature is made slow to release.

Inthe drawings Fig. l is a side view of a slow acting relay embodying the invention.

Fig. 2 is a view of the armature end.

Fig. 3 is a view of an armature provided with a short circuited winding.

In the drawing the frame 30 of magnetic material. has a pair of cores 31, and of magnetic material secured to the base thereof. Energizing windings and 34 surround the respective cores and are connected so that the upper ends of the cores 31 and 32- when magnetized will be of opposite magnetic polarity. An armature 35 of magnetic material overlies the cores 31 and 32 and has a pair of upwardly bent extensions 36 and 37 throu h which a pin 38 preferably of non-magnetic material extends. This pin also extends through inwardly bent lugs 39 and 40, carried by the frame 30, thus pivotally securing the armature 37 to the frame 30, and washers ll 0 f non-magnetic material are preferably provided between. the extensions 36 and 87 and the respective lugs 39 and L0 to reduce the magnetic leakage between the armature 35 and the upwardly extending portion 42 of the frame 30. An upstanding lug t?) is provided on the armature 35 and a spring 4:4; secured between this lug and the portion 452 of the frame 30 normally holds this arma ture in. its retracted position. An overlying portion 45 of the frame 30 carries an adjust ing screw 46 by which the air gap between the cores 31 and 32 and the armature can be regulated. The armature also carries an arm 4'? which can be used to impart movement to a variety of other apparatus. As shown, the arm 4-7 has a block of insulation 4=8 secured to the outer end thereof, which engages a spring contact l9. Uponattraction of the armature 35 thecontact l9 engages a contact and serves to control an electric circuit extending through these contacts. The contacts 49 and 50 can be conveniently mounted upon an extension Til of the frame 30.

A. second armature 52 as shoi n in. detail in Fig. 3 is also carried by the frame 30, a non-magnetic pin extending through lugs Fat and 553 of the frame 30 and extensions 56 on the armature 52, providing a pivotal mounting for this armature. Non-magnetic washers 57 are arranged between the lugs and and the extensions to prevent leakage of magnetic flux between the armature and the frame 30 so that the flux in the second armature will traverse the connecting bar 58 between the legs 59 and 60 thereof. A slnn't-circuited winding Gl, preferably of copper, surrounds the bar 58 and is preferably *ast thereon. The respective upper ends 62 and 63 of the legs :39 and 60 respectively are bent at right angles to the main portion thereof and shaped at their outer ends to partially surround the respective cores 31 and A pin 6-11: is carried by each of the legs 59 and 60, and each pin extends through an opening (35 in the portion 42 of the frame 30; the openings 65 being of such a size that the pins (it do not engage the walls thereof. A pair of pins 6 are also carried by the frame 230, and a spring 67' extending between each pin (36 and its respective pin G l. normally maintains the armature 35 in its retracted position. An adjusting screw (38 mounted in the portion .12 of the frame 30 serves to rcgu ate the air gap between the ends (32 and 68 of the arnnziure and the respective cores 31 and 32.

The end (33 of the armature supports an actuating arm (59., which can be used to impart movement to a variety of othc' apparatus. As shown a. block of insulation T0 is mounted to the outer end of tll, arm (3E) and engages a spring contact 71. designed to engage another contact not visible in the drawings, similar to the contact 50. Upon the attraction of the armature 35, these contacts are engaged and serve to control an electric circuit extending thercthrmigh. These contacts are conveniently mounted upon an extension 72 of the frame Sit), in the same way as the contacts if) and 51') are mounted on the extension Upon the completion of an energizing circuit through the windings 3-) and 3-1, a magnetic field is developed to ell'cct the attraction of both arinatures 255 and 52. The magnetic. circuit for armature extends from core 31, across armature to core 32. thence through core 32, and across base of frame 30 to core 31 while the magnetic circuit of armature extends from core 31, to the end 62; leg bar 58, leg 60 and end 63 of armature to core 32; thence through core 32, and across the base of the frame to the core 31. The cores 31 and 32 and the base of the frame 30 are thus common to both magnetic circuits. The current induced in the second ary winding 61 upon any change in the mag netic flux in the armature 52 develops a magnetic field which always opposes any change in the existing field. Thus, upon the energization or" the attracting windings 33 and 34, the winding 61 delays the building up of the flux in the armature 52 to the point at which it is drawn to the cores 31 and 32, and correspondingly delays the movement of the armature 52 the added inertia due to the mounting of the winding Glupon the armature also cooperating with the opposing flux to render this arn'iature slow, Operating. The direction cit the magnetic flux developed by the secondary winding 61, while opposite in direction to that in the armature 52 due to energization of the attracting windings 33 and 34:, is of less strength so that the flux developed by the secondary winding 61 at this time does not retard the attraction of armature 35.

Should the current through the attracting windings 33 and 34: be interrupted or diminished the strength of the magnetic field; developed thereby is correspondingly decreased without however changing its direction. Under these conditions the current induced in the secondary winding 61 by the change develops a magnetic field in the armature 52 of the same dircction within the magnetic circuit thereof as the field existing therein upon such interruption or diminution of current through the attracting windings 33 and 34c. The strength or the flux residual in the magnetic circuit of armature 52 is aug mented thereby, so that a longer interval occurs before the resultant flux is decreased to a point at which this armature is retracted, than would be the case were the secondary windings 61 omitted. The armature 52 is thereby rendered slow releasing, and it will be noted that the residual flux and that developed by the secondary winding is of the same direction within the magnetic circuit of this armature, thus materially incr asing the retardation in the release there oi. The added inertia of the ariina-ture due to the mounting of the winding 61 thereon, still further delays the return of the armature to its retracted position.

The residual flux in the normal magnetic circuit of armature 35 within the common portion of the magnetic circuits of the two armatures is of the same direction as that developed by the secondary winding 61, but the flux, residual in the magnetic circuit of armature 52 and that developed therein by the secondary winding 61, tending to flow through the armature 35 is oi a direction opposite to the flux residual in armature 35. This produces a more rapid diminution of the residual flux therein and permits the armature 35 to be retracted more quickly than would otherwise be the case.

In the operation of the electromagnetic device", upon initial cnergization of windings and 34, both armatures are attracted and engage their respective contact members 49 and 71 to complete their circuits. Upon momentary interruption or predetermined diminution of the current in the windings and 34, the armature 35 is quickly released thereby disengaging its respective contact members 49 and 50, while the armature 52 is maintained in its attracted position thereby maintaining contact member 71 and its associated member, not shown, in engagement for an appreciable interval. By controlling the intervals between the interruptions or predetermined CllIDlDUtlODS, the armature can be maintained in its at tracted position during such inteiTu'ptions ordiminutions and the armature 35 alternately retracted and" attracted in response thereto, while an interruption or diminution in excess of the determined. interval would effect the release of both armatures. Such an arrangement is particularly applicable to automatic telephone systems and the movement of the armature's canbe utilized to con trol a 'a riety of apparatus other than the circuit closures, such as 49 and being suitable, for example, to the operation of selector and scquenceswitches used in automatie telephony.

If desired the frame 30 may be of nonmagnetic material in which case a bar of magnetic material would preferably be mounted upon the base of the frame 30 and the lower ends of the cores 31 and 32 secured thereto, in order to still maintain an eflicient magnetic path between the lower end of the cores.

Vhat is claimed is:

1. An electromagnet having a plurality of independently movable armatures, a common energizing winding for moving said armatures, means on one of said armatures for delaying the movement thereof and means for adjusting the travelot each armature independently of the other armatures.

2. An electromagnetic device comprising two mechanically independent armatures, two normally parallel magnetic circuits each including one of the armatures, a short-air cuited winding abouta portion of one of the armatures to render it slow-operating, and an energizing winding to efiect the at traction of both arniatures arranged so that the field of force thereof traverses a portion of the two magnetic circuits common to both.

3. An electromagnetic device comprising two mechanically independent armatures, two normally parallel magnetic circuits each including one of the armatures, a. short-circuited winding about a portion of one of the armatures to render it slow-releasing, and an energizing winding to eliect the attraction of both armatures arranged so that the field oi torce thereof traverses a portion of the two magnetic circuits common to both.

4L An electromagnetic device comprising two mechanically independent armatures, two parallel magnetic circuits each including one oi the arm atin'es, a short-circuited winding about one of the armatures and an energizing winding to effect the attraction ot both of the armatures arranged so that the :field oi torec thereo't' traverses a por tion of the two magnetic circuits common to both.

An clectromzu gnetic device comprising two mechanically independent armatures, two parallel magnetic circuits each includ ing one of the armatures a short-circuite tl winding about one of said armatures, and an energizing winding to effect the vattraction of both of the armatures arranged so that the field of" force thereol traverses a portion of the two magnetic circuits.

6. An electromagnetic device comprising an armature, a magnetic circuit including substantially the entire armatrn'e, a second magnetic circuit arranged about and including a portion of the first circuit therein, an armature for said second magnetic circuit mechanically independent of said first armature, a short-circuited winding arranged about a portion 01 the second armature, and an energizing winding to effect ilttlflCtlOTl of both armatures arranged so that the field of force thereof traverses a portion oi the two magnetic circuits common to both; whereby the flux developed by the short-circuited winding incidental to interruption or diininution oi? the current in the energizing winding has a direction, within the portion of the magnetic circuit of and including the first armature, opposite to that of the flux residual therein upon such interruption or diminution, to accelerate the release o'l'- said first armature.

7. An electromagnetic device comprising two mechanically independent armatin'es, a magnetic circuit including one of the armatures in an individinrl. portion thereof, a second magnetic circuit including the other armature and arranged about and including a portion of the first circuit therein, a short circuitcd winding arranged about the second armature and an energizing winding to eflicct attraction of both armatures arranged so that the field of force thereof traverses a portion of the two magnetic circuits common toboth; whereby the flux developed by the short-circuited winding incidental. to interruption. or diminution of the current in the energizing winding is of the same direction in the second circuit and the common portion of the two circuits as the flux residual, therein and of an opposite direction within the portion or the first circuit including its respective armature therein as the flux residual in such portion ot the first circuit, to render the armature in the second circuit slow to release and to accelerate the release of the armature in the first circuit.

8. An electromagnetic device comprising two mechanically independent armatures, two parallel magnetic circuits each including one of the armatures in an individual. portion thereof, a short-circuited winding arranged about one armature and an cnergiz ing winding to elTect attraction of both armatures arranged so that the field 01 force therein traverses a portion of the two circuits common to both; whereby the flux developed by the short-eircuited winding incidental to interruption or diminution of the current in the energizing winding has a direction, within a portion of the normal eircuit of and including the other armature; opposite to the direction of the flux residual in the circuit of such other armature upon such interruption or diminution to accelerate the release of such other armature.

9. An electromagnetic device comprising two mechanically independent armatures a magnetic circuit including one of the arm atures, a second magnetic circuit including the other armature and arranged about and including a portion of the first circuit therein, a short-circuited winding about said second armatin'e, and an energizing winding to effect attraction of both armatures arranged so that the field of force thereof traverses a portion of the two circuits common to both; whereby the flux developerfl by the short-eircuited winding, incidental to the interruption or diminution of current in the energizing winding, is of the same direction within the entire portion of one of the mag netic circuits as the flux residual therein upon each interruption or diminution to render the armature included in such circuit slow to release.

In witness whereof, I hereunto subscribe my name this 31st day of January A. D. 1919.

HAROLD lV. GOFF. 

